Abstract: Based on a simplified gaseous chemical, the Hybrid, QSSA and Sklarew schemes are used to solve nonlinear chemical kinetic equations, and the results of different methods are compared. Also, the mass conservation techniques, such as error distribution and linear combination are applied to study their influence on the modeling results. It is found that three schemes make no difference to the calculations of the concentration of hydrocarbon, but some difference to those of other gaseous species. The result predicted from QSSA is similar to that from Sklarew, and the balance time of concentration of gaseous species is shorter for Hybrid than that for other two schemes. As a result, the mass conservation techniques can further improve the results. The error distribution technique is suitable for Hybrid and QSSA, and the linear combination is more suitable for QSSA